Photometry device

ABSTRACT

A photometry device for a camera is provided with a normal light sensor having a spectral sensitive characteristics close to those of a human eye, and a plurality of colorimetric sensors. The device further includes a photometry value determining system, a colorimetric compensation value determining system that determines a color of an object at each of the plurality of photometry areas and a colorimetric compensation value based on the determined color, and an exposure value determining system that compensates for the photometry value determined by the photometry value determining system for each of the plurality of photometry areas, and determines an exposure value based on the compensated photometry values. In the photometry device configured as above, the colorimetric compensation value determining system determines different colorimetric compensation values for different one of the plurality of photometry areas.

BACKGROUND OF THE INVENTION

The present invention relates to a photometry device applicable to anSLR (Single Lens Reflex) camera, and more particularly to a photometrydevice with which exposure errors due to a difference of reflectivity ofobjects having different colors can be compensated.

Recently, reflection type photometry devices have been employed in mostof cameras. The reflection type photometry device receives the light,which is reflected by an object and passed through an observing opticalsystem of a camera, using a light receiving element, determines thebrightness of the object based on the output of the measured value, andthen calculates the exposure value of the camera based on the measuredbrightness.

However, this type of the photometry device cannot detect the color ofthe object because of its structure. Accordingly, in such a device, thereflectivity of an object is generally assumed to be 18% and theexposure parameter is determined on this assumption. Therefore,regarding a whitish object whose reflectivity is greater than 18%, thedetermined brightness is greater than the actual brightness because thedetermined brightness assumes only 18% reflectivity contributing to thebrightness, when the reflectivity contribution is actually higher. Ifthe camera controls an exposure operation based on the determinedexposure value, the object is under exposed. A dark object whosereflectivity is less than 18% is measured to have a lower brightnessthan the actual brightness because the measured brightness assumes 18%reflectivity contributing to the brightness, when the reflectivity isactually lower. Therefore, such an object is over exposed. Thedifference of the reflectivity of the object may also occur depending onthe color of the object. For example, when the color of an object isyellow, the reflectivity may be up to 70%. In such a case, if thestandard reflectivity is assumed to be 18%, the exposure value isapproximately 2 Ev lower than necessary. If the object color is blue,the reflectivity is approximately 9%. In this case, the object is overexposed by approximately 1 Ev greater than necessary.

Therefore, when the conventional photometry device is used, thephotographer is required to guess the reflectivity of the object. Then,based on the reflectivity determined by the photographer, the exposureis controlled such that, if the object is a whitish or yellowish onehaving a relatively high reflectivity, it is to be overexposed, and ifthe object is a blackish or bluish one having a relatively lowreflectivity, it is to be underexposed. With this operation, theabove-described defects may be solved. However, accurately guessing thereflectivity of the object and controlling the exposure can only be doneby experienced and skilled photographers. It is impossible to requireall the photographers to do such an operation. Further, it is notpreferable that a manual operation of the photographer is required forexposure. Furthermore, if such a manual operation is required, camerasbecome unsuitable for automatic photographing which is the recent trend.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an improvedphotometry device with which appropriate exposure values can be obtainedwhen the device is configured such that a photographing frame is dividedinto a plurality of areas and colorimetric compensation values, whichare used for compensating an exposure value, are obtained at the dividedareas.

For the above object, according to the invention, there is provided aphotometry device for a camera, which is provided with a normal lightsensor that has a plurality of photometry areas and performs aphotometry operation with respect to an object at each of the pluralityof photometry areas, the normal light sensor having a spectral sensitivecharacteristics close to those of a human eye, a photometry valuedetermining system that determines an photometry value at each of theplurality of photometry areas in accordance with outputs of the normallight sensor corresponding to the plurality of photometry areas, aplurality of colorimetric sensors for colorimetry capable of performingphotometry with respect to each of the plurality of photometry areas,the plurality of colorimetric sensors having different spectralsensitivity characteristics, a colorimetric compensation valuedetermining system that determines a color of an object at each of theplurality of photometry areas in accordance with the outputs of theplurality of colorimetric sensors and determining a colorimetriccompensation value based on the determined color, and an exposure valuedetermining system that compensates for the photometry value determinedby the photometry value determining system for each of the plurality ofphotometry areas, and determines an exposure value based on thecompensated photometry values. In the photometry device configured asabove, the colorimetric compensation value determining system determinesdifferent colorimetric compensation values for different one of theplurality of photometry areas.

With this configuration, it becomes possible to determine appropriatecolorimetric compensation values depending on the arrangement of theareas within a photographing frame.

In a particular case, the colorimetric compensation value determiningsystem may determine the colorimetric compensation values such that acolorimetric compensation value at a peripheral area of a photographingframe is smaller than that of a central area of the photographing frame.

Alternatively, the colorimetric compensation value determining systemmay determine the colorimetric compensation values for the plurality ofphotometry areas depending on a distance of each photometry area withrespect to the center of a photographing frame.

In such a case, a colorimetric compensation value at an area fartherfrom the center of the photographing frame may be smaller than that atan area closer to the center of the photographing frame.

Further alternatively, the colorimetric compensation value determiningsystem may determine the colorimetric compensation values for theplurality of photometry areas depending on data intrinsic to aphotographing lens that forms an image of the object.

In this case, the data intrinsic to the photographing lens may includeat least one of a focal length of the photographing lens, an exit pupilposition of the photographing lens, and an open f-number of thephotographing lens.

Alternatively or optionally, the data intrinsic to the photographinglens may include a focal length of the photographing lens, and acolorimetric compensation value has a greatest absolute value when thefocal length is within a predetermined range, the colorimetriccompensation value being smaller when the focal length is greater orsmaller than the predetermined range.

In this case, the colorimetric compensation value may be determined as afunction of the focal length.

Alternatively or optionally, the data intrinsic to the photographinglens may include an exit pupil position of the photographing lens, and acolorimetric compensation value has a greatest absolute value when theexit pupil position is within a predetermined range, the colorimetriccompensation value being smaller when the exit pupil position is on afront side or rear side with respect to the predetermined range.

Also in this case, the colorimetric compensation value may be determinedas a function of the exit pupil position.

Still alternatively or optionally, the data intrinsic to thephotographing lens may include an open f-number of the photographinglens, and a colorimetric compensation value has a greatest absolutevalue when the open f-number is within a predetermined range. In thiscase, the colorimetric compensation value may be smaller when the openf-number is smaller or greater than the predetermined range.

In a particular case, the colorimetric compensation value may bedetermined as a function of the open f-number.

Further alternatively or optionally, the colorimetric compensation valuedetermining system may determine the colorimetric compensation valuesfor the plurality of photometry areas depending on an area correspondingto a part of an object on which a photographing lens is focused.

In this case, a colorimetric compensation value for an areacorresponding to a part of the object on which the photographing lens isfocused is greater than that for an area corresponding to another partof the object on which the photographing lens is not focused.

Optionally, the exposure amount determining system may have at least oneof:

a. a function of determining the exposure amount by performing a dividedphotometry, based on the compensated photometry values, in accordancewith a predetermined algorithm:

b. a function of determining the exposure amount by averaging thecompensated photometry values for the plurality of photometry areas;

c. a function of determining the exposure amount by performing thecenter-weighted averaging of the compensated photometry values; and

d. a function of determining the exposure amount by selecting one of thecompensated photometry values corresponding to the plurality of areas.

Further optionally, the normal light photometry sensor and the pluralityof colorimetric photometry sensors may be arranged on an eyepiece sideof a pentagonal prism of a single lens reflex camera, at least thenormal light photometry sensor being arranged at an upper centralportion of the pentagonal prism.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 shows a perspective view of a camera employing a photometrydevice according to the invention;

FIG. 2 schematically shows main components of the camera shown in FIG.1;

FIG. 3A shows an arrangement of photometry sensors;

FIG. 3B shows an alternative arrangement of photometry sensors;

FIG. 4A schematically shows a structure of each of the photometrysensors;

FIG. 4B shows a relationship between the photometry areas of eachphotometry sensor;

FIG. 5 shows spectral sensitivity characteristics of the green, blue andred light sensors;

FIG. 6 shows a block diagram of main portions of the camera;

FIG. 7 is a flowchart illustrating a main procedure of a photometryoperation according to an embodiment;

FIG. 8 is a flowchart illustrating the “lens communication procedure”;

FIG. 9 shows a flowchart illustrating the “photometry sensor Bvdcalculation procedure”;

FIG. 10 is a flowchart illustrating the “open aperture photometrycompensation calculation procedure”;

FIG. 11 is a flowchart illustrating the “colorimetry procedure”;

FIG. 12 is a flowchart illustrating the “light source compensationprocedure”;

FIG. 13 is a flowchart illustrating the “light source differencecompensation procedure”;

FIG. 14 is a flowchart illustrating the “colorimetric parametercalculation procedure”;

FIG. 15 is a flowchart illustrating the “colorimetric constants settingprocedure”;

FIG. 16 shows an example of constants read from the EEPROM;

FIGS. 17 and 18 show a flowchart illustrating the “color judgmentprocedure”;

FIG. 19 shows the “colorimetric compensation value calculationprocedure”;

FIG. 20 shows a relationship between types of compensation and figuresillustrating the compensation methods;

FIG. 21 is a flowchart illustrating an “exposure value (Lvd) calculatingprocedure”;

FIG. 22 is a flowchart illustrating an “exposure value determiningprocedure”; and

FIG. 23 is a flowchart illustrating a “divided photometry Lvdcalculation procedure.”

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, referring to the accompanying drawings, an embodimentaccording to the present invention will be described.

FIG. 1 shows a perspective view of a camera 1000 employing a photometrydevice according to the invention, and FIG. 2 schematically shows maincomponents of the camera 1000.

The camera 1000 has a camera body 1, to which a photographing lens 2 isdetachably coupled. The camera body 1 accommodates a quick return mirror3, a focusing glass 4, a pentagonal prism 5 (or a pentagonal mirror),and an eyepiece optical system 6. A part of the quick return mirror 3 isformed to be a half mirror 3 a (see FIG. 1), and behind the half mirror3 a, an auxiliary mirror 7 is provided. Light passed through the halfmirror 3 a is reflected by the auxiliary mirror 7, and is directedtoward a distance measuring device 8. The distance measuring device 8 isconfigured as a multi-point distance measuring device, and an AF(Automatic focusing) control is performed in accordance with themeasurement results of the distance measuring device 8.

On the rear side of the pentagonal prism 5, four photometry sensors 9(9D, 9R, 9G and 9B) are provided (see FIGS. 1 and 2), each of whichfunctions as a photometry element and receives part of light passedthrough the photographing lens 2. Based on the outputs of the photometrysensors 9, a photometry operation for determining exposure parameters isexecuted.

The photographing lens 2 and the camera body 1 are electricallyconnected through electrical contacts 10. Thus, a lens ROM 11 built inthe photographing lens 2 is electrically connected to a control circuit20 accommodated in the camera body 1. On an outer surface of the camerabody 1, an LCD (liquid crystal display) 21, and various buttons such asa release button 22 and a photometry mode changeover switch 28 areprovided. Furthermore, inside the camera body 1, various mechanisms suchas a film winding mechanism are provided. However, such mechanisms areconventionally known, and description thereof will be omitted for thesake of simplicity.

FIG. 3A shows a rear view of the pentagonal prism 5. As shown in FIG.3A, the four photometry sensors 9 includes sensors 9D and 9G provided atan upper central portion on the eyepiece side of the pentagonal prism 5,and sensors 9B and 9R are provided at lower side portions on theeyepiece side of the pentagonal prism 5. The photometry sensors 9D, 9G,9B and 9R are mounted on an FPC (flexible printed circuit board) 91 andfixedly positioned at the above-described respective positions by theFPC 91. In front of (i.e., on the pentagonal prism side of) each of thephotometry sensors 9D, 9G, 9B and 9R, an imaging lens 92 is provided toform an object image on each of the sensors 9D, 9G, 9B and 9R (see FIG.2).

FIG. 4A schematically shows a structure of each of the sensors 9D, 9G,9B and 9R. As shown in FIG. 4A, each sensor 9 (9D, 9G, 9B or 9R) isconstructed as a planar structure photometry IC chip that is configuredsuch that a light receiving section and an amplifier AMP are integrallyformed. The light receiving section includes six photometry areas, i.e.,a central area A0, a left area A1, a right area A2, an upper area A3, alower area A4, and a peripheral area A5. FIG. 4B shows a relationshipbetween the photometry areas A0-A5 and portions of an object. P0-P2shown in the photometry areas A0-A2 represent distance measuring points,respectively. The photometry areas A0-A5 of each sensor receives thelight from respective portions of an object as indicated in FIG. 4B.

The photometry sensor 9G is provided with a green filter GF on its lightreceiving surface, and receives a green component of light, thephotometry sensor 9B is provided with a blue filter BF on its lightreceiving surface, and receives a blue component of light, and thephotometry sensor 9R is provided with a red filter RF on its lightreceiving surface, and receives a red component of light. In thisembodiment, the three sensors 9G, 9B and 9R are used as colorimetryelements. Spectral sensitivity characteristics of the sensors 9G, 9B and9R respectively provided with the green, blue and red filters GF, BF andRF are indicated in FIG. 5. The sensors 9G, 9B and 9R have peaks insensitivity at approximately 540 nm, 420 nm, and 620 nm, respectively.

The remaining sensor 9D is not provided with a color filter, but asensitivity compensation filter is provided so that the spectralsensitivity characteristic of the sensor 9D has its peak within awavelength range of 500-600 nm, which is close to the visual sensitivitycharacteristic. The sensor 9D is used as a normal light detectingsensor.

FIG. 6 shows a block diagram of main portions of the camera 1000. Thefour sensors 9D, 9G, 9B and 9R output values indicative of quantity ofreceived light (components) to the controller 20, respectively. Further,the output (i.e., a distance value) of the distance measuring device 8is transmitted to the controller 20, which controls the AF device 25 toperform the automatic focusing operation.

Furthermore, the controller 20 is connected with a photometry switch SWSand a shutter-release switch SWR. The photometry switch SWS is ON whenthe release button 22 is half depressed. The shutter-release switch SWRis ON when the shutter button is fully depressed. When the shutterbutton 22 is depressed halfway and the photometry switch SWS is turnedON, the controller 20 performs a photometry calculation in accordancewith a predetermined algorithm, and calculates an exposure value. Then,the controller 20 controls the exposure control device 23 in accordancewith the calculated exposure value to perform a photographing operation.Further, the controller 20 drives a display driver 24 to display thecalculated exposure value on the LCD panel 21. It should be noted thatthe controller 20 includes an EEPROM 26 storing various values necessaryfor the photometry calculation (which will be described in detaillater), and a RAM 27 for temporarily storing various pieces of data.Further to the above, when the exposure value is determined, aphotometry mode signal indicative of one of photometry modes (e.g.,area-divided photometry, averaged photometry, central area weightedphotometry, a spot photometry and the like) is transmitted from thephotometry mode changeover switch 28 to the controller 20.

An operation of the photometry device will be described hereinafter.

A procedure shown in FIG. 7 is a main procedure of a photometryoperation. When the release button 22 is half depressed and thephotometry switch SWS is ON (S11: YES), a “lens communication procedure”is performed (S12) so that the controller 20 receives data intrinsic tothe photographing lens 2 currently mounted onto the camera body 1.Specifically, the data intrinsic to the photographing lens 2 includes anopen f-number (full aperture), a focal length of the photographing lens2, an exit pupil position and the like, which may affect the photometrycalculation. The data is transmitted from a lens ROM 11 of thephotographing lens 2 to the controller 20 through the electricalcontacts 10. In S12A, a distance measuring operation is performed withrespect to the distance measuring points P0-P2. Then, a “photometrysensor output Bvd calculation procedure” is executed (S13). In thisprocedure, the photometry sensors 9 (9D, 9G, 9B and 9R) output analogphotometry values which are obtained by receiving light through thephotographing lens 2, the quick return mirror 3, and the pentagonalprism 5. Then, the analog values are converted into digital brightnessvalues Bvd which can be used in the operation executed by the controller20.

It should be noted that the photometry is performed for each of thephotometry areas A0-A5, and photometry values Bvd(i) (i being integers0-5 corresponding to the photometry areas A0-A5). Then, using thephotometry values Bvd(i) obtained in S13 and the data intrinsic to thephotographing lens 2 obtained in S12, an “open aperture photometrycompensation calculation procedure” is performed in S14, therebyindividual photometry errors depending on the photographing lens 2 beingcanceled.

At S15, based on the brightness values Bvd(i) corresponding to thesensors 9R, 9B and 9G for the RGB (Red, Green and Blue) colorcomponents, a “colorimetry procedure” is executed to determine the colorof an object for each of the photometry areas A0-A5. Then, for each ofthe photometry areas A0-A5, a colorimetric compensation value CC(i) iscalculated based on the determined color of the object by executing an“colorimetric compensation value calculation procedure.” In S17, an“exposure value calculating procedure” is executed, where thecolorimetric compensation values CC(i) are added to the photometryvalues Bvd(i), respectively, and an exposure value Lvd for each of thephotometry areas A0-A5 is obtained based on the compensated photometryvalues Bvd(i). In the exposure value calculation procedure (S17), inaccordance with the photometry mode set by the photometry modechangeover switch 28, a calculation method is determined, and then,based on the photometry values Bvd(i), the exposure value Lvd iscalculated using the determined calculation method.

At S18, if the shutter-release switch SWR is ON (S18: YES), the exposurecontrol device 23 controls the exposure operation at S20 in accordancewith the exposure value Lvd obtained at S17 to execute a photographingoperation. If the shutter-release switch SWR is OFF, controls goes toS19, where it is detected whether a photometry timer is OFF.

If the photometry timer is ON (i.e., if a predetermined period has notelapsed)(S19: NO), control proceeds to S12, and the foregoing proceduresare repeated. If the photometry timer is OFF (i.e., if the predeterminedperiod has elapsed) (S19: YES), control proceeds to S11.

FIG. 8 is a flowchart illustrating the “lens communication procedure”,which is called at S12 of the main procedure shown in FIG. 7.

In the lens communication procedure, the controller 20 accesses the lensROM 11 through the electrical contacts 10, and retrieves the dataintrinsic to the photographing lens 2 stored in the lens ROM 11 (S101).The retrieved data is stored in the RAM 27 of the controller 20, andcontrol returns. Items included in the data intrinsic to thephotographing lens 2 include, for example, a lens type, lens data, theshortest focusable distance, a focusable range, a focal length of thephotographing lens, an exit pupil position, an open f-number, anaperture efficiency and the like. In this embodiment, the controller 20reads at least the focal length, the exit pupil position, the openf-number and the aperture efficiency, and stores the data in the RAM 27.

FIG. 9 shows a flowchart illustrating the “photometry sensor Bvdcalculation procedure”, which is called at S13 in the main procedureshown in FIG. 7.

In this procedure, digital data values Bvad(i) (where, i=0, 1, . . . ,5) which represents A/D converted output voltages (analog data) of thephotometry areas Ai (i=0, 1, . . . , 5) shown in FIG. 4A of thephotometry sensor 9D for normal light are obtained. Further, dataBvad·g(i), Bvad·b(i) and Bvad·r(i) which represent A/D converted valuesof the output voltages of the photometry areas Ai (i=0, 1, 2, . . . 5)of each of the sensors 9G, 9B and 9R for color components are obtained.Then, the A/D converted values Bvad(i) of the sensor 9D output areadjusted to brightness values Bvd(i) (S111). The A/D converted valuesBvad·g(i), Bvad·b(i) and Bvad·r(i) (i=0, 1, 2, . . . 5) are alsoadjusted to the brightness values Bvd·g(i), Bvd·b(i) and Bvd·r(i),respectively (S112). It should be noted that the A/D conversion methodemployed in S111 and S112 is a well-known method for converting aquantity of analogue value into digital data, and therefore, descriptionthereof is not given herein.

FIG. 10 is a flowchart illustrating the “open aperture photometrycompensation calculation procedure” which is called at S14 of the mainprocedure shown in FIG. 7.

At S121, an open aperture photometry compensation value Mnd1(i) iscalculated based on the focal length, the exit pupil position, the openf-number and the aperture efficiency which have been retrieved from theROM 11 and stored in the RAM 27.

The open aperture photometry compensation values Mnd1(i) are obtained asfollows. Firstly, compensation values mv1, mv2, mv3 and mv4 forcompensating for shift amounts with respect to the reference photometryvalues due to the individual differences of the optical characteristicsof the cameras, and the focal length, the exit pupil position, the openf-number and the aperture efficiency, are determined. Then, the sum ofthe compensation values mv1+mv2+mv3+mv4 is obtained, which sum isreferred to as the open aperture compensation value Mnd1(i). Similarly,corresponding to the photometry sensors 9G, 9B and 9R, the open aperturecompensation values Mnd1·g(i), Mnd1·b(i), and Mnd1·r(i) are calculated.Then the open aperture compensation value Mnd1(i) is added to thebrightness value Bvd(i), and then the sum is determined as a newbrightness value Bvd(i). Thus, the following calculation is executed atS121:

Bvd(i)=Bvd(i)+Mnd 1(i).

Similar to the above, with respect to the brightness values Bvd·g(i),Bvd·b(i) and Bvd·r(i) obtained by the photometry sensors 9G, 9B and 9R,open aperture photometry compensation values Mnd1·g(i), Mnd1·b(i) andMnd1·r(i) are added to obtain newly defined brightness values (S122).That is:

Bvd·g(i)=Bvd·g(i)+Mnd 1·g(i).

Bvd·b(i)=Bvd·b(i)+Mnd 1·b(i).

Bvd·r(i)=Bvd·r(i)+Mnd 1·r(i).

As a result, each brightness value is free from the affect of theindividual differences of photographing lenses 2 coupled to the camerabody 1.

At S15 of the main procedure shown in FIG. 7, a colorimetry procedure iscalled, which is shown in FIG. 11. In the “colorimetry procedure”, thecolor of the object is detected, and in S16, the “colorimetry procedure”is called and colorimetric compensation values CC(i) are calculated inaccordance with the detected color of the object.

FIG. 11 is a flowchart illustrating the “colorimetry procedure” calledat S16 of the main procedure.

At S21, colorimetric parameters are initialized (i.e., set to initialvalues). At S22, a “light source compensation procedure” is executed toobtain compensation values for the effects of the color temperature ofthe light source. At S23, a “light source difference compensationprocedure” is executed using the compensation values obtained at S22. AtS24, a “colorimetric parameter calculation procedure” for obtainingcolorimetric parameters, which will be used for execution of a“colorimetric judgment procedure”, is executed. At S25, a “colorimetricconstants setting procedure” is executed to set constants used for colormeasurement. At S26, a “color judgment procedure” for judging a colorbased on the parameters and constants obtained in the preceding steps isexecuted.

FIG. 12 shows a flowchart illustrating the “light source compensationprocedures” called at S22 of FIG. 11.

In the embodiment, when the initial Bvd value of the photometry sensors9 is determined, a predetermined light source (light source A) is used.When a photographing is to be executed, the Bvd should be compensated inaccordance with the actually used light source, for example, thesunlight. In the procedure shown in FIG. 12, relative compensationvalues of B (blue) and R (red) components with respect to the value forthe G (green) component are obtained, and the compensation is performed.

Specifically, for the color components G, B and R, the brightness dataBvd·light·g, Bvd·light·b, and Bvd·light·r, are retrieved from the EEPROM26 (S141). Then, a light source adjustment value adj·sun·b for thephotometry sensor 9B and a light source adjustment value adj·sun·r forthe photometry sensor 9R with respect to the value for G component areretrieved from the EEPROM 26 (S142). The light source adjustment valuesare as follows.

adj·sun·b=+8

adj·sun·r=−4

It should be noted that, if the adjustment of the sensors 9 is executedusing the sun light instead of the predetermined light source A, thelight source adjustment values are all zero.

Then, based on the brightness data and the light source adjustmentvalues, a light source compensation value light·gb for the photometrysensor 9B is obtained as follows (S143).

light·gb=Bvd·light·g−Bvd·light·b+adj·sun·b

Similarly, a light source compensation value light·gr for the photometrysensor 9R is obtained as follows (S144).

light·gr=Bvd·light·g−Bvd·light·r+adj·sun·r

FIG. 13 is a flowchart illustrating the “light source differencecompensation procedure”, which is called at S23 in FIG. 11. In thisprocedure, based on the light source compensation values for light·gband light·gr, the light source compensation is applied to the brightnessvalues Bvd·b(i) and Bvd·r(i) (i=0-5) obtained at areas A0-A5 of thephotometry sensors 9B and 9R, respectively.

At S151, for each photometry area of the photometry sensor 9B, thefollowing calculation is executed.

Bvd·b(i)=Bvd·b(i)+light·gb.

At S152, for each photometry area of the photometry sensor 9R, thefollowing calculation is executed.

Bvd·r(i)=Bvd·r(i)+light·gr.

With the above compensation, the photometry sensors 9G, 9B and 9R hasthe same photometric characteristics for the external light source suchas the sunlight.

FIG. 14 is a flowchart illustrating the “colorimetric parametercalculation procedure”, which is called at S24 of FIG. 11. In thisprocedure, colorimetric parameters used in the colorimetric judging arecalculated. As the colorimetric parameters, parameters Gf(i) for Gcomponent, parameters Bf(i) for B component, and parameters Rf(i) for Rcomponent are calculated (S161, S162 and S163) according to thefollowing formulae.

Gf(i)=Bvd·g(i)−{Bvd·b(i)+Bvd·r(i)}/2;

Bf(i)=Bvd·b(i)−{Bvd·g(i)+Bvd·r(i)}/2; and

Rf(i)=Bvd·r(i)−{Bvd·b(i)+Bvd·g(i)}/2.

FIG. 15 is a flowchart illustrating the “colorimetric constants settingprocedure”, in which the colorimetric constants are retrieved from theEEPROM 26. The colorimetric constants include: threshold values forcolor judgment; coefficients for color judgment; coefficients forcalculating colorimetric compensation values; and adjustment values forcalculating the colorimetric compensation values, which are representedby valuables as indicated below:

threshold values for color judgment: THvalue·*1(i);

coefficients for color judgment: coefficient·#1(i) andcoefficient·#2(i);

coefficients for calculating colorimetric compensation values:CCcoefficient·*1(i);

adjustment values for calculating the colorimetric compensation values:CCadjestment·*1(i).

In the above indication, a symbol * represents g (green), b (blue), r(red), m (magenta), y (yellow) or c (cyan), and a symbol # represents g(green), b (blue) or r (red).

In this procedure, for all the photometry areas A0-A5 of the sensors 9,the colorimetric constants are set, respectively. Therefore, at S171, iis set to zero (0), and then, if i≦5 (S172: YES), the constants are readfrom the EEPROM (S173, S174, S175 and S176). Then, at S177, i isincremented by one, and control returns to S172. Thus, for i=0 through5, steps S173-S176 are repeated. The constants read from the EEPROM 26are stored in the RAM 27 of the controller 20. FIG. 16 shows an exampleof the constants read from the EEPROM 26.

FIGS. 17 and 18 show a flowchart illustrating the “color judgmentprocedure”. The procedure judges the color of the object for eachphotometry area A0-A5.

At S181, i is set to 0. Then, if i≦5 (S182: YES), the following stepsare repeated. In the following description. Color(i) represents colorparameters, and Color·max(i) and Color·min(i) represent color judgmentparameters.

At S183, the color parameter Color(i) is set to colorless. Then, atS184, Rf(i) and THvalue·c1(i) are compared.

If Rf(i)<THvalue·c1(i) (S184:YES), |Bf(i)−Gf(i)| and|coefficient·r1(i)×Rf(i)| are compared (S185).

If |Bf(i)−Gf(i)|<|coefficient·r1(i)×Rf(i)| (S185:YES), Color·min(i) isset to Rf(i) (S186).

If Rf(i)≧THvalue·c1(i) (S184:NO) or|Bf(i)−Gf(i)|≧|coefficient·r1(i)×Rf(i)| (S185:NO), step S186 is skipped.

At S187, Gf(i) is compared with THvalue·m1(i).

If Gf(i)<THvalue·m1(i) (S187:YES), |Bf(i)−Rf(i)| and|coefficient·g1(i)×Gf(i)| are compared (S188).

If |Bf(i)−Rf(i)|<|coefficient·g1(i)×Gf(i)| (S188:YES), Color·min(i) isset to Gf(i) (S189).

If Gf(i)≧THvalue·m1(i) (S187:NO) or|Bf(i)−Rf(i)|≧|coefficient·g1(i)×Gf(i)| (S188:NO), step S189 is skipped.

At S190, Gf(i) is compared with THvalue·g1(i).

If Gf(i)>THvalue·g1(i) (S190:YES), |Bf(i)−Rf(i)| and|coefficient·g2(i)×Gf(i)| are compared (S191).

If |Bf(i)−Rf(i)|<|coefficient·g2(i)×Gf(i)| (S191:YES), Color·max(i) isset to Gf(i) (S192).

If Gf(i)≦THvalue·g1(i) (S190:NO) or|Bf(i)−Rf(i)|≧|coefficient·g2(i)×Gf(i)| (S191:NO), step S192 is skipped.

At S193, Bf(i) is compared with THvalue·b1(i).

If Bf(i)>THvalue·b1(i) (S193:YES), |Gf(i)−Rf(i)| and|coefficient·b2(i)×Bf(i)| are compared (S194).

If |Gf(i)−Rf(i)|<|coefficient·b2(i)×Bf(i)| (S194:YES), Color·max(i) isset to Bf(i) (S195). If Bf(i)≦THvalue·b1(i) (S193:NO) or|Gf(i)−Rf(i)|≧|coefficient·b2(i)×Bf(i)| (S194:NO), step S195 is skipped.

At S196, Rf(i) is compared with THvalue·r1(i).

If Rf(i)>THvalue·r1(i) (S196:YES), |Bf(i)−Gf(i)| and|coefficient·r2(i)×Rf(i)| are compared (S197).

If |Bf(i)−Gf(i)|<|coefficient·r2(i)×Rf(i)| (S197:YES), Color·max(i) isset to Rf(i) (S198). If Rf(i)≦THvalue·r1(i) (S196:NO) or|Bf(i)−Gf(i)|≧|coefficient·r2(i)×Rf(i)| (S197:NO), step S198 is skipped.

At S199, Bf(i) is compared with THvalue·y1(i).

If Bf(i)<THvalue·y1(i) (S199:YES), |Gf(i)−Rf(i)| and|coefficient·b1(i)×Bf(i)| are compared (S200).

If |Gf(i)−Rf(i)|<|coefficient·b1(i)×Bf(i)| (S200:YES), Color·min(i) isset to Bf(i) (S201). If Bf(i)≧THvalue·y1(i) (S199:NO) or|Gf(i)−Rf(i)|≧|coefficient·b1(i)×Bf(i)| (S200:NO), step S201 is skipped.

During the above steps, for each of the photometry areas A0-A5,color·max(i) and color·min(i) are obtained.

At S202 (FIG. 18), it is jedged whether color·min(i) is equal to Rf(i).If color·min(i) is equal to Rf(i) (S202:YES), color(i) is set to cyan(S203). If color·min(i) is not equal to Rf(i), S203 is skipped. Then, itis judged whether color·min(i) is equal to Gf(i) at S204. Ifcolor·min(i) is equal to Gf(i) (S204:YES), color(i) is set to magenta(S205). If color·min(i) is not equal to Gf(i), S205 is skipped. Next, itis judged whether color·max(i) is equal to Gf(i) at S206. Ifcolor·max(i) is equal to Gf(i) (S206:YES), color(i) is set to green(S207). If color·max(i) is not equal to Gf(i) (S206:NO), S207 isskipped. In S208, it is judged whether color·max(i) is equal to Bf(i).If color·max(i) is equal to Bf(i), color(i) is set to blue (S209). Ifcolor·max(i) is not equal to Bf(i) (S208:NO), then S209 is skipped. InS210, it is judged whether color·max(i) is equal to Rf(i). Ifcolor·max(i) is equal to Rf(i) (S210:YES), then color(i) is set to red(S211). If color·max(i) is not equal to Rf(i) (S210:NO), S211 isskipped. In S212, it is judged whether color·min(i) is equal to Bf(i).If color·min(i) is equal to Bf(i) (S212:YES), color(i) is set to yellow(S213), and control proceeds to S214. If color·min(i) is not equal to Bf(i) (S212:NO), step S213 is skipped, and control proceeds to S214, wherei is incremented by one. Then, control proceeds to S182. As a result ofthe above-described procedure, yellow has the highest priority, and inthe foregoing steps, the color finally selected in accordance with theconditions is determined as the color of the photometry area. Since theabove procedure is repeated for i=0 to i=5, the color of each of thephotometry areas A0-A5 is determined.

After the color judgment is performed as described above, the“colorimetric compensation value calculation procedure” as shown in FIG.19 is called at S16 of the flowchart shown in FIG. 7.

In this procedure, the colorimetric compensation values CC(i)corresponding to the difference of the colors among the photometry areasare calculated.

At S221, i is set to an initial value of zero. At S222, it is judgedwhether i is equal to or smaller than five, or greater than five. If iis 0, 1, 2, 3, 4 or 5, (S222:YES), it is judged whether color(i) iscolorless (S223). If color(i) is colorless (S223:YES), CC(i) is set tozero (S224). If color(i) is not colorless (S223:NO), step S224 isskipped. At S225, it is judged whether color(i) is cyan. If color(i) iscyan (S225:YES), the colorimetric compensation value CC(i) is set to Cin S226. If color(i) is not cyan (S225:NO), then step S226 is skipped.

At S227, it is judged whether color(i) is magenta. If color(i) ismagenta (S227:YES), the colorimetric compensation value CC(i) is set toM in S228. If color(l) is not magenta (S227:NO), then step S228 isskipped.

At S229, it is judged whether color(i) is green. If color(i) is green(S229:YES), the colorimetric compensation value CC(i) is set to G inS230. If color(i) is not green (S229:NO), then step S230 is skipped.

At S231, it is judged whether color(i) is blue. If color(i) is blue(S231: YES), the colorimetric compensation value CC(i) is set to B inS232. If color(i) is not blue (S231:NO), then step S232 is skipped.

At S233, it is judged whether color(i) is red. If color(i) is red(S233:YES), the colorimetric compensation value CC(i) is set to R inS234. If color(i) is not red (S233:NO), then step S234 is skipped.

At S235, it is judged whether color(i) is yellow. If color(i) is yellow(S235:YES), the colorimetric compensation value CC(i) is set to Y inS236. If color(i) is not yellow (S235:NO), then step S236 is skipped.Then, at S237, i is incremented by one, and control returns to S222. Bythe above procedures for i=0 to i=5, each of the colorimetriccompensation values CC(i) is set to Y, M, C, B, G or R.

In the following procedure, for the determined values of Y, M, C, B, Gor R for each of the colorimetric compensation values CC(i), a numericalvalue is assigned to obtain a numerical value of the colorimetriccompensation value CC(i). FIG. 20 shows a relationship of conditions (A)through (E) for compensation, and TABLEs indicating the numericalvalues.

As understood from FIG. 20, there are conditions in which thecompensation of the colorimetric compensation values is performed ornot. The latter condition is indicated as condition (A) in FIG. 20. Theformer is further divided into four conditions, which include: condition(B) where the colorimetric compensation values, which are modified inaccordance with a distance from the center of the photographing frame,are selected, or the colorimetric compensation values are calculated inaccordance with a distance from the center of the photographing frame;condition (C) where the colorimetric compensation values, which aremodified in accordance with the data intrinsic to the photographinglens, are selected; condition (D) where the colorimetric compensationvalues are calculated in accordance with the data intrinsic to thephotographing lens; and condition (E) where the colorimetriccompensation values, which are modified in accordance with the focusingcondition data, are selected.

TABLE 1 shows the colorimetric compensation values corresponding to thesymbols Y, M, C, B, G and R, which are stored in the EEPROM 27.

TABLE 1 Symbol colorimetric compensation value Y −8 M 0 C 0 B +6 G 0 R+2

It should be noted that the values shown in TABLE 1 are default values,which are used when the modification or calculation as in conditions(B)-(E) will not be performed.

TABLE 2 indicates the colorimetric compensation values which aremodified in accordance with the distance with respect to the center ofthe photographing frame. The values indicated in TABLE 2 are stored inthe EEPROM 27.

TABLE 2 colorimetric compensation values Symbol 0 ≦ Yd < 2.5 2.5 ≦ Yd <8.5 8.5 ≦ Yd Y −8 −4 −2 M 0 0 0 C 0 0 0 B +6 +3 +1 G 0 0 0 R +2 +1 0

A relationship between the photometry areas A0-A5 and the distance Ydfrom the center of the photographing frame is indicated in TABLES 3 and4. The relationship shown in TABLEs 3 and 4 is stored in the EEPROM 27.

TABLE 3 longer side Yd (mm) photometry area   0 ≦ Yd ≦ 2.5 A0 2.5 ≦ Yd <8.5 A1, A2 8.5 ≦ Yd A5

TABLE 4 shorter side Yd (mm) photometry area   0 ≦ Yd ≦ 2.5 A0 2.5 ≦ Yd< 5.6 A3, A4 5.6 ≦ Yd A5

It should be noted that, for the photometry area A5, the value in TABLE3 or TABLE 4 is selected depending on the side along which the image isformed.

When the colorimetric compensation value is assigned to each photometryarea A(i), the distance Yd is determined based on TABLEs 3 and 4, andthen an appropriate value indicated in TABLE 2 is selected.

TABLE 5 indicates alternative modification of the colorimetriccompensation values which may also be stored in the EEPROM 27. In TABLE5, the colorimetric compensation values are provided by a function ofYd.

TABLE 5 Symbol colorimetric compensation values Y Yd − 10 (Y ≦ 0) M 0 C0 B −Yd/2 + 6 (B ≧ 0) G 0 R −Yd/3 + 3 (R ≧ 0)

In the embodiment, the amount (i.e., the absolute value) of thecolorimetric compensation value is smaller for a farther point. Forexample, in TABLE 2, the value of Y is −8 for 0≦Yd<2.5, is −4 for2.5≦Yd<8.5, and is −2 for 8.5<Yd. Further, the values for M, C and R arefixed to zero.

TABLE 6 shows the colorimetric compensation values for condition (C). Inthis example, as the data intrinsic to the photographing lens 2, theexit pupil position, the open f-number, and the focal length arereferred to. Depending on the data intrinsic to the photographing lens,one of columns A, B and C in TABLE 6 is selected.

TABLE 6 colorimetric compensation values Symbol A B C Y −8 −4 −2 M 0 0 0C 0 0 0 B +6 +3 +1 G 0 0 0 R +2 +1 0

TABLEs 7-9 show which of the columns A-C of TABLE 6 is to be selecteddepending on the exit pupil, open f-number and focal length,respectively. The conditions indicated in TABLEs 7-9 are stored in theEEPROM 26.

TABLE 7 Exit Pupil position (1/Exp) selected column Exitp < 40 C 40 ≦Exitp < 60 B  60 ≦ Exitp < 120 A 120 ≦ Exitp < 200 B 200 ≦ Exitp C

TABLE 8 Open f-number selected column Avmin < 1.5 C 1.5 ≦ Avmin < 2.5 B2.5 ≦ Avmin < 3.5 A 3.5 ≦ Avmin < 4.5 B 4.5 ≦ Avmin C

TABLE 9 Focal Length (mm) selected column FL < 24 C 24 ≦ FL < 40 B  40 ≦FL < 100 A 100 ≦ FL < 300 B 300 ≦ FL C

As understood from the TABLEs 6-9, values for M, C and G are set to afixed value of zero. For Y, B and R, when the exit pupil position, theopen f-number or the focal length has a central value, colorimetriccompensation values having the greatest absolute values are selected,and when the exit pupil position, the open f-number or the focal lengthdecreases or increased with respect to the central value, thecolorimetric compensation values having smaller absolute values areselected.

TABLEs 10-12 show the colorimetric compensation values for condition(D). In this example, as the data intrinsic to the photographing lens 2,the exit pupil position, the open f-number, and the focal length arereferred to. Depending on the data intrinsic to the photographing lens,the colorimetric compensation values are calculated. It should be notedthat the coefficients of the formulae shown in TABLEs 10-12 are storedin the EEPROM 26.

TABLE 10 shows a relationship between the colorimetric compensationvalues and the exit pupil position Exitp. As indicated in TABLE 10,depending on whether the exit pupil position is greater than 80 or not,Y, B and R are calculated in accordance with different formulae. Thevalues for M, C and G are fixed to zero.

TABLE 10 colorimetric compensation value Symbol Exitp ≦ 80 80 < Exitp Y−0.1 × Exitp (Y ≦ 0) 0.05 × Exit − 12 (Y ≦ 0) M 0 0 C 0 0 B  0.1 × Exitp− 2 (B ≧ 0) −0.05 × Exitp + 10 (B ≧ 0) G 0 0 R 0.05 × Exitp − 2 (R ≧ 0)−0.05 × Exitp + 6  (R ≧ 0)

TABLE 11 shows a relationship between the colorimetric compensationvalues and the open f-number Avmin. As indicated in TABLE 11, dependingon whether the Avmin is greater than 3 or not, Y, B and R are calculatedin accordance with different formulae. The value for M, C and G arefixed to zero.

TABLE 11 colorimetric compensation value Symbol Avmin ≦ 3 3 < Avmin Y −2× Avmin − 2 (Y ≦ 0)  2 × Avmin − 14 (Y ≦ 0) M 0 0 C 0 0 B 2 × Avmin (B ≧0) −2 × Avmin + 12 (B > 0) G 0 0 R Avmin − 1 (R ≧ 0) −1 × Avmin + 5 (R ≧0) 

TABLE 12 shows a relationship between the colorimetric compensationvalues and the focal length FL. As indicated in TABLE 12, depending onwhether FL is greater than 50 or not, Y, B and R are calculated inaccordance with different formulae. The values for M, C and G are fixedto zero.

TABLE 12 colorimetric compensation value Symbol FL ≦ 50 50 < FL Y −0.15× FL − 0.5 (Y ≦ 0)  0.05 × FL − 10.5 (Y ≦ 0) M 0 0 C 0 0 B  0.1 × FL + 1(B ≧ 0)   −0.05 × FL + 8.5 (B > 0)  G 0 0 R  0.05 × FL − 0.5 (R ≧ 0)−0.05 × FL + 4.5 (R ≧ 0) 

It should be noted that the values calculated in accordance with theabove formulae are close to the values obtained in accordance withcondition (C) with reference to TABLE 6.

TABLE 13 shows the colorimetric compensation values for condition (E).In this example, depending on the focusing condition, the colorimetriccompensation values are selected. It should be noted that thecoefficients of the values shown in TABLE 13 are stored in the EEPROM26.

In the camera according to the embodiment, distance measuring points P0,P1 and P3 are provided, which correspond to the photometry areas A0, A1and A2. In TABLE 13, depending on whether the photometry areas A0, A1and A2 are focused or not, the colorimetric compensation values for Y, Band R are selected. The values for M, C and G are fixed to zero.

TABLE 13 colorimetric compensation value area A0 areas A1 and A2 Symbolfocused not focused focused Not focused Y −8 −4 −6 −2 M 0 0 0 0 C 0 0 00 B +6 +3 +4 +2 G 0 0 0 0 R +2 +1 +1 +1

As understood from TABLE 13, the colorimetric compensation values for Y,B and R are smaller when the areas A1 and A2 are focused than a casewhere the area A0 is focused. The colorimetric compensation values forM, C and G are fixed to zero.

After the color compensation values CC(i) are set as described above(S16 in FIG. 7), an “exposure value calculation procedure is executed.

FIG. 21 is a flowchart illustrating the “exposure value calculatingprocedure”, which is called at S17 of the main procedure shown in FIG.7. The “exposure value calculation procedure” is a procedure forobtaining a suitable exposure value Lvd by applying compensation basedon a photographing condition to the brightness values Bvd(i) for thephotometry areas A0-A5 of the normal light sensor 9D, which are obtainedin S13 and compensated in S14 (FIG. 7). Specifically, in this procedure,for example, by comparing the brightness values Bvd(i) with each otheror by evaluating the brightness values Bvd(i) as a whole, aphotographing conditions, e.g., a rear light photographing, amagnification and/or scene of photographing, is judged. Then, based onthe photographing condition as judged, the exposure value Lvd iscalculated by applying a predetermined algorithm with respect to thebrightness values Bvd(i). For example, the exposure value Lvd suitableto the photographing condition may be determined by weighted-averagingthe brightness values Bvd(i), or by selecting one of the brightnessvalues Bvd(i).

In S131, a colorimetric compensation calculation is executed. In thecolorimetric compensation calculation, colorimetric compensation valuesCC(i) for the photometry areas A0-A5 are added to the brightness valuesBvd(i) for the photometry areas A0-A5, respectively, to obtain thecompensated brightness values Bvd(i). That is:

 Bvd(i)=Bvd(i)+CC(i)

Then, in accordance with the setting of the photometry mode selectionswitch 28, a photometry mode flag is set (S132). At S133, an “exposurevalue calculation procedure” is executed to calculate the exposure valueLvd in accordance with the photometry mode represented by the photometrymode flag.

FIG. 22 shows a flowchart illustrating the “exposure value calculationprocedures” which is called at S133 of the flowchart shown in FIG. 21.

In S301, the photometry mode flag is checked. Depending on thephotometry mode flag, control diverges to one of S302, S303, S304 andS305. Specifically, when the photometry mode flag represents the dividedphotometry, control proceeds to S302 and a divided-photometry exposurevalue Lvd is calculated. If the photometry mode flag represents theaveraging photometry, control proceeds to S303 and anaveraged-photometry exposure value Lvd is calculated. If the photometrymode flag represents the center-weighted photometry, control proceeds toS304 and a center-weighted photometry exposure value Lvd is calculated.If the photometry mode flag represents the spot photometry, controlproceeds to S305 and a spot photometry exposure value Lvd is calculated.

FIG. 23 shows a flowchart illustrating a “divided-photometry exposurevalue calculation procedure”, in which the exposure value Lvd isdetermined based on the compensated brightness values Bvd(i). Firstly,based on the compensated brightness values Bvd(i) for the photometryareas A0-A5 of the sensor 9D, parameters for calculating the exposurevalue Lvd is obtained (S311). Then, the parameters are compensated basedon an upper limit of the brightness (S312), a rear light condition(S313), weighted parameter calculation (S314), a photographingmagnification (S315), a photographing scene (S316) a positivecompensation for the high brightness photographing scene (S317). Then,based on the compensated parameters, the exposure value Lvd is obtained(S318).

When the averaged-photometry exposure value is obtained at S303 of FIG.22, the exposure value Lvd is calculated merely by averaging thebrightness values Bvd(i) as follows:

Lvd={Bvd(0)+Bvd(1)+Bvd(2)+Bvd(3)+Bvd(4)+Bvd(5)}/6

When the center-weighted exposure value is obtained at S304 of FIG. 22,the exposure value Lvd is calculated based on the following formula:

Lvd={(Bvd(0)×4)+Bvd(5)+(Bvd(1)+Bvd(2)+Bvd(3)+Bvd(4))×/4}/8

When the spot-photometry exposure value is obtained at S305 of FIG. 22,the maximum value of the brightness values Bvd(i) is selected. That is:

 Lvd=max {Bvd(0), Bvd(1), Bvd(2), Bvd(3), Bvd(4), Bvd(5)}

Alternatively, the brightness value Bvd(0) of the central photometryarea A0 may be used as the exposure value Lvd.

If the thus calculated exposure value Lvd is input to a not-shownexposure control device, which controls the exposure operation of thecamera, an object can be photographed at an appropriate exposure valueregardless of the difference of colors (i.e., the difference of thereflectivity).

Specifically, when the object color is determined to be yellow, theexposure compensation value is determined so that the object isoverexposed, and when the object color is determined to be blue or red,the exposure compensation value is determined so that the object isunderexposed. Thus, the difference of reflectivity depending on thecolor of the object can be resolved, and an appropriate exposure can beperformed.

According to the above-described embodiment, each of the photometrysensor for the normal light, and those for the colorimetry has aplurality of photometry areas, and the exposure value is calculatedbased on the compensated photometry values. In particular, thecolorimetric compensation value obtained by the colorimetric judgment ineach photometry area is modified depending on the distance from thecenter of the photographing frame, the exit pupil position, the openf-number, the focal length, the photographing condition at a photometryarea corresponding to the distance measuring area.

With this configuration, the colorimetric compensation values of yellow,blue and red, which greatly affects the exposure value, are modifiedsuch that, for example, the colorimetric compensation values at theperipheral areas are smaller that those at the central areas, therebythe effects of the color of an object located at the peripheral portionof the photographing frame are reduced, and a central part of the objectis appropriately exposed. Thus, the effects of the erroneouscompensation due to the inferior photometry accuracy at the peripheralportion are eliminated with this configuration. It should be noted that,in the above-described embodiment, compensation corresponding to the G,M and C components are not provided since these components have lesseffect to the exposure value.

In the above-described embodiment, as shown in FIG. 3A, the sensor 9Dfor the normal light is arranged at an upper central potion on theeyepiece side of the pentagonal prism 5. Thus, with respect to theobject, the sensor 9D for the normal light is arranged at thesymmetrically central position. Therefore, it becomes possible to setthe photometry sensitivity distribution of the sensor 9D is madesymmetrically with respect to the center thereof, and obtain highphotometry accuracy at the central area of the pentagonal prism 5, whicharea has a higher priority in photometry operation. That is, at thecenter of the pentagonal prism 5, a difference of angles formed betweenthe optical axis of the photographing lens 2 and the optical axis of theeyepiece optical system 5 can be made small. Therefore, a substantiallyall the photographing angle range can be covered using the sensor 9D forthe normal light.

In the above-described embodiment, the sensor 9D for the normal light isprovided in addition to the sensors 9B, 9G and 9R for B, G and R colorcomponents. The light receiving characteristics of the sensor G has apeak at the wavelength of 540 nm. This characteristic is close to thatof the sensor 9D. Therefore, in another embodiment of the invention, thesensor 9G is used instead of the sensor 9D, and the sensor 9D isomitted, as shown in FIG. 3B. In such a case, in steps S11-S15 of themain procedure (FIG. 7), the output Bvad·g of the sensor 9G is used asBvad, and the calculation is to be executed.

With this configuration, the photometry device includes only threephotometry sensors. Since the number of the sensors is reduced, such astructure contributes to reduction of the manufacturing cost. Further,the omission of one sensor contributes to the downsizing of the camerabody. It should be noted that, in FIG. 3B, the photometry sensor 9G islocated at an upper central position on the eyepiece side of thepentagonal prism 5 as the normal light photometry sensor 9D in FIG. 3A.With this structure, the photometry sensitivity distribution can be madesymmetrical with respect to the center thereof, thereby the accuracy ofthe photometry sensor 9G can be improved.

The present disclosure relates to the subject matter contained inJapanese Patent Application No. 2000-350732, filed on Nov. 17, 2000,which is expressly incorporated herein by reference in its entirety.

What is claimed is:
 1. A photometry device for a camera, comprising: anormal light sensor that has a plurality of photometry areas andperforms a photometry operation with respect to an object at each ofsaid plurality of photometry areas, said normal light sensor having aspectral sensitive characteristics close to those of a human eye; aplurality of colorimetric sensors for colorimetry capable of performingphotometry with respect to each of said plurality of photometry areas,said plurality of colorimetric sensors having different spectralsensitivity characteristics; a photometry value determining system thatdetermines an photometry value at each of said plurality of photometryareas in accordance with outputs of said normal light sensorcorresponding to said plurality of photometry areas; a colorimetriccompensation value determining system that determines a color of anobject at each of said plurality of photometry areas in accordance withthe outputs of said plurality of colorimetric sensors and determining acolorimetric compensation value based on the determined color; and anexposure value determining system that compensates for the photometryvalue determined by said photometry value determining system for each ofsaid plurality of photometry areas, and determines an exposure valuebased on the compensated photometry values, wherein said colorimetriccompensation value determining system determines different colorimetriccompensation values for different one of said plurality of photometryareas.
 2. The photometry device according to claim 1, wherein saidcolorimetric compensation value determining system determines thecolorimetric compensation values such that a colorimetric compensationvalue at a peripheral area of a photographing frame is smaller than thatof a central area of the photographing frame.
 3. The photometry deviceaccording to claim 1, wherein said colorimetric compensation valuedetermining system determines the colorimetric compensation values forthe plurality of photometry areas depending on a distance of eachphotometry area with respect to the center of a photographing frame. 4.The photometry device according to claim 3, wherein a colorimetriccompensation value at an area farther from the center of thephotographing frame is smaller than that at an area closer to the centerof the photographing frame.
 5. The photometry device according to claim1, wherein said colorimetric compensation value determining systemdetermines the colorimetric compensation values for the plurality ofphotometry areas depending on data intrinsic to a photographing lensthat forms an image of the object.
 6. The photometry device according toclaim 5, wherein the data intrinsic to the photographing lens includesat least one of a focal length of said photographing lens, an exit pupilposition of said photographing lens, and an open f-number of saidphotographing lens.
 7. The photometry device according to claim 5,wherein the data intrinsic to the photographing lens includes a focallength of said photographing lens, and wherein a colorimetriccompensation value has a greatest absolute value when the focal lengthis within a predetermined range, the colorimetric compensation valuebeing smaller when the focal length is greater or smaller than thepredetermined range.
 8. The photometry device according to claim 7,wherein the colorimetric compensation value is determined as a functionof the focal length.
 9. The photometry device according to claim 5,wherein the data intrinsic to the photographing lens includes an exitpupil position of said photographing lens, and wherein a colorimetriccompensation value has a greatest absolute value when the exit pupilposition is within a predetermined range, the colorimetric compensationvalue being smaller when the exit pupil position is on a front side orrear side with respect to the predetermined range.
 10. The photometrydevice according to claim 9, wherein the colorimetric compensation valueis determined as a function of the exit pupil position.
 11. Thephotometry device according to claim 5, wherein the data intrinsic tothe photographing lens includes an open f-number of said photographinglens, and wherein a colorimetric compensation value has a greatestabsolute value when the open f-number is within a predetermined range,the colorimetric compensation value being smaller when the open f-numberis smaller or greater than the predetermined range.
 12. The photometrydevice according to claim 11, wherein the colorimetric compensationvalue is determined as a function of the open f-number.
 13. Thephotometry device according to claim 1, wherein said colorimetriccompensation value determining system determines the colorimetriccompensation values for the plurality of photometry areas depending onan area corresponding to a part of an object on which a photographinglens is focused.
 14. The photometry device according to claim 13,wherein a colorimetric compensation value for an area corresponding to apart of the object on which the photographing lens is focused is greaterthan that for an area corresponding to another part of the object onwhich the photographing lens is not focused.
 15. The photometry deviceaccording to claim 1, wherein said exposure value determining system hasat least one of: a. a function of determining the exposure amount byperforming a divided photometry, based on the compensated photometryvalues, in accordance with a predetermined algorithm; b. a function ofdetermining the exposure amount by averaging the compensated photometryvalues for said plurality of photometry areas; c. a function ofdetermining the exposure amount by performing the center-weightedaveraging of the compensated photometry values; and d. a function ofdetermining the exposure amount by selecting one of the compensatedphotometry values corresponding to said plurality of areas.
 16. Thephotometry device according to claim 1, wherein said normal lightphotometry sensor and said plurality of colorimetric photometry sensorsare arranged on an eyepiece side of a pentagonal prism of a single lensreflex camera, at least said normal light photometry sensor beingarranged at an upper central portion of said pentagonal prism.
 17. Thephotometry device according to claim 1, wherein said colorimetriccompensation value determining system determines the colorimetriccompensation values for said plurality of photometry areas depending onat least one of a distance of each photometry area with respect to acenter of a photographing frame, a focal length of a photographing lens,an exit pupil position of said photographing lens, an open f-number ofsaid photographing lens, and an area corresponding to a part of anobject on which said photographing lens is focused.
 18. A photometrydevice for a camera, comprising: a normal light sensor that has aplurality of photometry areas and performs a photometry operation withrespect to an object at each of said plurality of photometry areas, saidnormal light sensor having spectral sensitive characteristics close tothose of a human eye; a plurality of colorimetric sensors forcolorimetry capable of performing photometry with respect to each ofsaid plurality of photometry areas, said plurality of colorimetricsensors having different spectral sensitivity characteristics; aphotometry value determiner that determines a photometry value at eachof said plurality of photometry areas in accordance with outputs of saidnormal light sensor corresponding to said plurality of photometry areas;a colorimetric compensation value determiner that determines a color ofan object at each of said plurality of photometry areas in accordancewith outputs of said plurality of colorimetric sensors and determining acolorimetric compensation value based on the determined color; and anexposure value determiner that compensates for the photometry valuedetermined by said photometry value determiner for each of saidplurality of photometry areas in accordance with the colorimetriccompensation value determined by said colorimetric compensation valuedeterminer, and determines an exposure value based on the compensatedphotometry values; wherein said colorimetric compensation valuedeterminer determines colorimetric compensation values for saidplurality of photometry areas.
 19. The photometry device according toclaim 18, wherein said colorimetric compensation value determinerdetermines the colorimetric compensation values such that a colorimetriccompensation value at a peripheral area of a photographing flame issmaller than that of a central area of the photographing frame.
 20. Thephotometry device according to claim 18, wherein said colormetriccompensation value determiner determines the colorimetric compensationvalues for the plurality of photometry areas depending on a distance ofeach photometry area with respect to a center of a photographing frame.21. The photometry device according to claim 20, wherein a colorimetriccompensation value at an area farther from the center of thephotographing frame is smaller than that at an area closer to the centerof the photographing frame.
 22. The photometry device according to claim18, wherein said colorimetric compensation value determiner determinesthe colorimetric compensation values for the plurality of photometryareas depending on data intrinsic to a photographing lens that forms animage of the object.
 23. The photometry device according to claim 22,wherein the data intrinsic to the photographing lens includes at leastone of a focal length of said photographing lens, an exit pupil positionof said photographing lens, and an open f-number of said photographinglens.
 24. The photometry device according to claim 22, wherein the dataintrinsic to the photographing lens includes a focal length of saidphotographing lens, and wherein a colorimetric compensation value has agreatest absolute value when the focal length is within a predeterminedrange, the colorimetric compensation value being smaller when the focallength is outside the predetermined range.
 25. The photometry deviceaccording to claim 24, wherein the colorimetric compensation value isdetermined as a function of the focal length.
 26. The photometry deviceaccording to claim 22, wherein the data intrinsic to the photographinglens includes an exit pupil position of said photographing lens, andwherein a colorimetric compensation value has a greatest absolute valuewhen the exit pupil position is within a predetermined range, thecolorimetric compensation value being smaller when the exit pupilposition is one of a front side and a rear side with respect to thepredetermined range.
 27. The photometry device according to claim 26,wherein the colorimetric compensation value is determined as a functionof the exit pupil position.
 28. The photometry device according to claim22, wherein the data intrinsic to the photographing lens includes anopen f-number of said photographing lens, and wherein a colorimetriccompensation value has a greatest absolute value when the open f-numberis within a predetermined range, the colorimetric compensation valuebeing smaller when the open f-number is not within the predeterminedrange.
 29. The photometry device according to claim 28, wherein thecolorimetric compensation value is determined as a function of the openf-number.
 30. The photometry device according to claim 18, wherein saidcolorimetric compensation value determiner determines the colorimetriccompensation values for the plurality of photometry areas depending onan area corresponding to a part of an object on which a photographinglens is focused.
 31. The photometry device according to claim 30,wherein a colorimetric compensation value for the area corresponding tothe part of the object on which the photographing lens is focused isgreater than a colorimetric compensation value for an another areacorresponding to another part of the object on which the photographinglens is not focused.